Separation of isotopes of naturally occurring elements is an often difficult and time-consuming process. However, isotope separation is very useful in that the separated isotopes often have a variety of uses. For example, heavy hydrogen, or in other words, deuterium, is very valuable in isotope tracing studies wherein the heavy hydrogen can be traced through reactions in order to study the precise reaction mechanism. Also, heavy hydrogen is valuable as a moderator in nuclear reactors. It will also be one of the fuel constituents in fusion reactors. The abundance of deuterium in nature is about 1 part per 6,500 parts of hydrogen-1, hereinafter often referred to as light hydrogen.
Lithium exists in two isotope forms, lithium-6 and lithium-7. Lithium-6 comprises about 7% of natural lithium. Lithium-6 is valuable not only as a tracer isotope for lithium but also will certainly have value in fusion reactors as a precursor to tritium which is formed by the bombardment of lithium-6 with slow neutrons to provide helium and tritium.
As therefore can be seen, deuterium is a valuable isotope of hydrogen and correspondingly lithium-6 is a very valuable isotope of lithium. However, in nature the abundance ratios of both deuterium and lithium-6 are relatively small. Therefore, to be useful the deuterium and the lithium-6 must be concentrated and separated from the more abundant light hydrogen and lithium-7 isotopes.
Accordingly, one object of this invention is to provide a process which separates light hydrogen from heavy hydrogen.
Another object of this invention is to provide a process which separates lithium-6 from lithium-7.
Yet another object of this invention is to provide a process which separates light hydrogen from heavy hydrogen by performing a plurality of reactions of an alkali metal amalgam with water, taking advantage of the fact that in each reaction stage the reaction rate of light hydrogen containing water with the alkali metal amalgam is faster than the reaction rate of the heavy hydrogen containing water.
Yet another object of this invention is to provide a process which concurrently separates lithium-6 from lithium-7 and light hydrogen from heavy hydrogen.
A still further object of this invention is to provide a concurrent separation process for separating lithium-6 from lithium-7 and light hydrogen from heavy hydrogen which, because it is concurrent, may be substantially more economically feasible than independently run processes for separation of lithium isotopes and hydrogen isotopes.
Yet another object of this invention is to provide a separation process which concurrently separates lithium-6 from lithium-7 and light hydrogen from heavy hydrogen, lithium-6 being separated from the lithium-7 by partial electrolysis in a mercury cell, with the resulting lithium-6 enriched amalgam reacting with water to provide lithium hydroxide solution wherein the solution is lithium-6 enriched and deuterium enriched.
The method of accomplishing these and other objects of the invention will become apparent from the detailed description of the invention which follows.